Process of preparing boron-iron alloys



Patented Nov. 17, 1925.

7 1,562,042 PATENT OFFICE.

UNITED STATES ALADAR PACZ, OF CLEVELAND HEIGHTS, OHIO, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

PROCESS OF PREPARING BORON-IRON ALLOYS.

N0 Drawing. Application filed May 3, 1919, Serial No. 294,456. Renewed April 7, 1925.

To all whom it may concern:

Be it known that I, Amman PACZ, a citi- Zen of the United States, residing at Cleveland Heights, in the county of Cuyahoga, State of Ohio, have invented certain new and useful Improvements in Processes of Preparing Boron-Iron Alloys, of which the following is a specification.

My inventionrelates to so-called alloy steels and to methods and means for rendering them more easily fusible and therefore rendering them of more service in the arts. These steels include one or more of the rarer metals such as tungsten, chromium, vanadian, manganese, silicon, nickel, molybdenum, zirconium, tantalum, uranium, columbium, cobalt and others. The

use of my invention makes it feasible to cast such steels into articles which have hereto fore been made by forging or otherwise working the metal. It also improves the quality of such alloy steels as are ultimately forged or otherwise worked.

According to my invention, boron is incorporated in the steel along with one or more of the' aforesaid rarer metals. The action of the boron'is probably to alloy with the steel as well as to act as a scavenger. This is to be distinguished from the action of such materials as boric acid and other boron compounds.

The amount of boron in the final product may vary depending upon the degree of fusibility desired. The best results are obtained when from three-fourths er cent to four or five per cent boron are inc uded in the final steel and, when a greater amount is included, the results are not so satisfactory both from the standpoint of economy and effect obtained. The amount of boron will depend to a certain extent on the carbon content since the higher carbon steels have generally the lower melting points.

One application of my invention is to the production of high speed steel which can be cast readily into cutters and other tools. In one instance, a high speed steel containing three-fourths per cent boron, seventeen per cent tungsten, five per cent chromium, threefourths per cent vanadium and sixty-five one-hundredths per cent carbon was cast' into a cutting tool. Hammer dies were made from a steel containing three-tenths per cent vanadium, one and one-half per cent chromium, and four-tenths per cent boron. Examples of the many alloy steels to which my invention is applicable are the so called stainless steels, motor valve steels and construction steels, for instance those used for automobile parts and machinery in general. By incorporating a relatively small per cent .of the boron with the other alloy metals such as the tungsten and others hereinbefore referred to, a comparatively easily fusible steel is obtained which can be cast readily even into intricate forms sub stantially free from blow holes and other defects and which still preserves the properties which are given to the metal by the alloying element exclusive of the boron.

I have produced steels with a low content of nickel or chromium, for instance one and four-tenths per cent nickel or one and two tenths per cent chromium, with one-tenth to two-tenths per cent boron which had physical characteristics equal or superior to those of steels having much higher contents of the nickel or chromium but containing no boron. It is true that when such small proportions of boron are incorporated the effect on the melting point is not so pronounced and by incorporating more boron the fusibility may be increased. From this standpoint my invention comprises the utilization of boron to replace a part of the other rarer metals such as nickel, chromium and others.

I prefer to introduce the boron alloyed with other metals, usually iron. It is desirable also to have a certain .amountof aluminum or aluminum and silicon present. This result is obtained preferably by utilizing, the alumino-thermic method for the production of the boron alloy. This method consists in mixing together the oxides of the alloying metals including a certain amount of boronv compound such as boric acid and aluminum and igniting the mixture. I prefer to utilize the alumino-thermic method which is disclosed in my copending application Serial N 0. 255,790 filed September 26, 1918, in which specific refence is made to a method of producing an allo of zirconium. According to that met 0d, the materials are made into briquettes consisting of the oxides of the various alloying metals and finely divided aluminum preferably of the blown variety. A certain amount of flaky aluminum can be incorporated in the briquettes, at least in the briquette which is initially ignited, since this method contemplates the ignition of one or more briquettes initially and the addition subsequently, of enough briquettes to produce the desired amount of alloy. The 0.\'- ides of the tungsten, ChlUlllillll'l or other metal to be incorporated in the alloy may be included in the briquette so that the metal will be reduced at the same time as the boron. It is a fact that the presence of the boron improves the alloy became its efl'ect in lowering the melting causes the alloy to be more readily absorliied when added to metal baths. To produce an alloy eontaining approximatel v sixteen per cen boron, a mixture of one thousand and titty grams of Fe t) six hundred and thirty grains of 13 0 seven hundred. and seventy grams of linely divided aluminum ot the' blown variety and fifteen grams of the flaky aluminum were mixed and formed into a briquette with the addition 01' sodium silicate as a binder. The reaction was started preferably by igniting a small briquette having a high per cent of the flakyaluminum in a blast lamp and dropping it into a crucible containing a number of briquettes ot' the composition just described. After the reaction has progressed, more briquettes were added until the desired amount of product was obtained. This product contained about three to six per cent aluminum and a slight amount. of silicon derived from the binder. As hereinbe't'ore stated, the aluminum and silicon are of advantage since they have a very etlicient deoxidizing action.

The boron alloy produced as above described may be added to the molten bath of the other metals or otherwise inctn'porated. Preferably the materials added to the molten bath contains not only the boron but also the other rare metal or metals.

Most of the specific steels hereinbefore referred to will be found to contain in addition to the boron and iron at least one other hat: I claim as new and desire to secure by Letters Patent of the United States, is F 1,. The process of making an alloy containing boron which consists in briquetting a. boron compound with a compound of ariother metal and finely divided aluminium, and igniting the briquette to cause the said materials to react.

2. The process of making an alloy containing iron and boron which consists in briquetting a boron compound. with an iron compound and finely divided aluminum. and igniting the bri uette to cause a reaction between the said materials.

3. The process ol making an taining iron, boron and consists in briquetting a boron compound. an iron compound and a compound of the other metal with tinely divided aluunnum, and igniting the briquette to cause a reac tion between the said materials.

4. The process ot making an alloy containing iron and boron which ,consists in brlquetting oxides of boron and iron with finely divided aluminum, and igniting the briquette to cause a reaction between the said materials.

5. The process of producing an allov con taining iron and boron which consists in briquetting oxides of boron and iron with finely divided aluminum of the blown variety, and igniting the briquette to cause a reaction between the said materials.

6. The process of producing ferro-boron which consists in briquetting oxides of boron and iron with finely diyided aluminum, and ignitii'ig the briquette to produce a reaction between the said materials.

In witness whereof, I have hereunto set my hand this first day of May, 1919.

ALADAR PACZ.

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